Lithium inks and electrodes and batteries made therefrom

Abstract

Lithium metal powder based inks are provided. The inks are provided in formulations suitable for printing using a variety of printing techniques, including screen printing, offset litho printing, gravure printing, flexographic printing, pad printing and inkjet printing. The inks include lithium metal powder, a polymer binder and optionally electrically conductive materials and/or lithium salts in a solvent. The inks are well suited for use in printing electrodes for use in lithium metal batteries. Batteries made from lithium powder based anodes and electronic applications such as RFID labels, Smart Cards and wearable medical devices are also provided.

1. A lithium ink for use in printing an electrode for a lithium battery, the ink comprising;
 20 to 80 percent lithium metal powder; 
 10 to 25 percent of a polymer binder; 
 optionally, an electrically conductive material other than lithium metal powder; 
 a lithium salt; and 
 a solvent; 
 wherein the percentages are calculated on a dry weight basis; and 
 wherein the lithium metal powder is formed by dispersing molten lithium metal in an inert medium and cooling the dispersion to below the melting point of the lithium. 
 
     
     
       2. The lithium ink of  claim 1 , wherein the polymer is capable of complexing with lithium salts and participating in ionic conduction. 
     
     
       3. The lithium ink of  claim 2 , wherein the polymer binder comprises a polyimide, a polybenzimidazole or a polyamide-imide. 
     
     
       4. The lithium ink of  claim 1 , wherein the polymer binder comprises a polymer selected from the group consisting of polyamides, polyphenylene oxides, polyarylates, polyester-imides, polyester-amide-imides, poly(benzoxazoles), polysulfones, polyether sulfones, polysulfonamides, poly(quinoxaline), poly(para-phenylenes), poly(aryl ethers) substituted with a pyridyl group, poly(aryl ether sulfones), polyepoxides and combinations thereof. 
     
     
       5. The lithium ink of  claim 1 , wherein the polymer has a glass transition temperature of at least 150° C. 
     
     
       6. The lithium ink of  claim 3 , wherein the polyimide comprises a pre-imidized, amorphous, thermoplastic polyimide powder that is soluble in a polar solvent. 
     
     
       7. The lithium ink of  claim 1 , wherein the lithium metal powder has an average particle size of no more than about 50 microns. 
     
     
       8. The lithium ink of  claim 1 , wherein the lithium metal powder has an average particle size of no more than about 1 micron. 
     
     
       9. The lithium ink of  claim 3 , wherein the polymer binder comprises a polyimide. 
     
     
       10. The lithium ink of  claim 1 , wherein the solvent comprises gamma-butyrolactone. 
     
     
       11. A method comprising:
 printing the lithium ink of  claim 1  onto a substrate; and 
 allowing the ink to dry to form a printed layer on the substrate. 
 
     
     
       12. The method of  claim 11 , wherein printing is selected from the group consisting of: screen printing, offset litho printing; gravure printing; flexographic printing; pad printing and ink jet printing. 
     
     
       13. The method of  claim 11 , wherein the printed layer has an average thickness of 40 microns or less. 
     
     
       14. The method of  claim 12 , wherein printing comprises screen printing. 
     
     
       15. The method of  claim 14 , wherein the printed layer has an average thickness of no more than 30 microns. 
     
     
       16. The method of  claim 12 , wherein printing comprises flexographic printing. 
     
     
       17. The method of  claim 16 , wherein the printed layer has an average thickness of 0.5 to 5 microns. 
     
     
       18. The method of  claim 12 , wherein printing comprises ink jet printing. 
     
     
       19. The method of  claim 18 , wherein the printed layer has an average thickness of 0.1 to 30 microns. 
     
     
       20. A method of making a battery comprising first and second metal current collectors, an anode, a cathode and a polymer electrolyte layer comprising:
 printing the lithium ink of  claim 1  onto the first metal current collector; 
 allowing the ink to dry to form the cathode; 
 printing a composition comprising a polymer binder, a lithium salt and a solvent on the cathode; 
 allowing the composition to dry to form the polymer electrolyte layer; and 
 printing the anode on the polymer electrolyte layer and placing the second metal current collector on the anode; or 
 printing the anode onto the second metal current collector and placing the printed anode on the second metal current collector in contact with the electrolyte layer. 
 
     
     
       21. The lithium ink of  claim 1 , wherein the lithium ink has a viscosity of 1 to 30 Pa-sec at 25° C. 
     
     
       22. The lithium ink of  claim 1 , wherein the lithium ink has a viscosity of at least 10 Pa-sec at 20° C. 
     
     
       23. The lithium ink of  claim 1 , wherein the lithium ink comprises 10 to 30 percent lithium salt on a dry weight basis. 
     
     
       24. The lithium ink of  claim 1 , wherein the ink comprises an electrically conductive material other than lithium metal powder. 
     
     
       25. The lithium ink of  claim 24 , wherein the electrically conductive material comprises carbon. 
     
     
       26. The lithium ink of  claim 1 , wherein the polymer binder comprises a polymer selected from the group consisting of: polyvinylidene fluoride; polyethylene oxide; polyethylene; polypropylene; polytetrafluoroethylene; polyacrylates; mixtures thereof and copolymers thereof. 
     
     
       27. The lithium ink of  claim 1 , wherein the ink has a viscosity of 10 to 100 Pa-sec at 20° C. 
     
     
       28. The lithium ink of  claim 1 , wherein the lithium ink comprises:
 20 to 50 percent lithium metal powder; 
 10 to 25 percent of a polymer binder; 
 15 to 40 percent of a conductive material; 
 wherein the percentages are calculated on a dry weight basis. 
 
     
     
       29. The lithium ink of  claim 28 , wherein the ink has a viscosity of 0.5 to 50 Pa-sec at 25° C. 
     
     
       30. The lithium ink of  claim 1 , wherein the lithium ink comprises 5 to 25 percent of a lithium salt on a dry weight basis. 
     
     
       31. The lithium ink of  claim 1 , wherein the lithium ink comprises 10 to 15 percent of a lithium salt on a dry weight basis.